Abstract
Nodal signaling is important for craniofacial development. The wdr68 gene is required for craniofacial development and expression of the Nodal target genes lefty1 and lefty2 (lft1/2). The dyrk1b gene is also required for lft1/2 expression. Supporting a role for wdr68 as a transcriptional regulator, we found that fusing a transcriptional repression domain, Mad to wdr68 interfered with its functions while fusion to a transcriptional activation domain, Cebp did not. We also found that the zebrafish Dyrk1b and Wdr68 proteins can interact in vitro. To identify the interaction domain in Dyrk1b, a series of Dyrk1b deletion fragments were made. These deletions showed the central kinase domain and C-terminal region of Dyrk1b are not essential for physical interaction. However, these efforts did not identify the WID. The N-terminal 109 amino acids (N109) of Dyrk1b are thought to harbor a nuclear localization signal (NLS). We hypothesize the WID lies within the N109 region. The positive and negative controls were full length Dyrk1b and Luciferase, respectively. Additional details of the mapping experiments will be presented.